Hi.
You can create any count of placemarks on map.
After that call module and pass map id.
The other way if you have different plcemarks on different maps and want to show it on one. - Yes, that you can do too, just create map, and in placemark list or category list or group list enter what you want to see on that map. In this case I collect all placemarks depends on belonging to (groups, categories) and show it.

As for resposive - it easy for width, but is a little bit hard for height.
If you set width = 0, you'll get 100% width. But for height - no, because I wrome many times, templates have nested divs, and if you want to have 100% height for some div, you ave to set 100% for all parent divs for it.
You can see on my demo - you can show it as a full screen.

As for social - you can publish maps in any article or K2 item by plugin call. But you have to configure map before, ie it is not easy create rich map on the fly when you write an article, therefore today there is no any "button" integration with other extensions.